Amy Winehouse packed quite a punch at the Glastonbury music festival this past weekend.

After taking the stage Saturday, the troubled singer, 25, climbed down into the pit and scuffled briefly with a concertgoer.

It was unclear what sparked the altercation, but witnesses say a fan tried to grab Winehouse.

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Winehouse sang for about an hour in front of an estimated crowd of 80,000.

The singer also reportedly called hip-hop artist Kanye West the "c-word" during the concert. On his blog, Kanye UniverseCity, West said "This just in... Amy Winehouse hates me!!! Now I've really made it!!! LOL!!!"

She shocked fans last week by performing at a special birthday concert for Nelson Mandela.

The performance came just after she was hospitalized. Her father says she developed emphysema from smoking cigarettes and crack cocaine, although her spokeswoman has said Winehouse only has pre-emphysema symptoms.

Click here to read Kanye West's blog entry.

The Associated Press contributed to this report.